Printing and duplicating



Maj 29, 1923. g 1,456,754 I D. GESTETNER PRINTING AND DUiLICATING FiledDeb. 9, 1919 Patented May 29, 1923.

TED ST "res DAVID GESTETNER, OF LONDON, ENGLAND, ASSTG-NOR TO D.GESTETNER, LIMI'JIED, OF

LONDON, ENGLAND.

PRINTING AND DUPLIGA'IING.

Application filed December 9,1919. Serial No. 343,662.

To all whom it may cont-em:

Be it known that I, DAVID GES'I'ETNER, a subject of the King of GreatBritain and Ireland, and residin at Neo Cyclostyle Works, Tottenham ale,London, N. 17,

England, have invented certainlnew and useful Improvements in andRelating, to Printing and Duplicating, of which the following IS aspecification.

- This invention relates to printing or duplicating with the aid ofstencils produced upon Yoshino or like paper or on a suitable textilefabric such as bolting cloth, by the employment of a photographicprocess of the kind in which the action of light is made use of forchanging the solubility of a composition as, for instance, bichromatedgelatine in regard to a solvent liquid used as a developer.

Processes of this kind are described in the specification of UnitedStates patent to Waters No. 1,327,931, January 13, 1920, and in thespecification accompanying my prior United States Patent No. 1,354,478,grant-- ed October 5, 1920.

In the operation of such processes, it is found that where inkedsurfaces of relative- 1y considerable width or area are formed in theprinting operation, there is a pronounced tendency for the ink to spreadon the impression receiving surface or for the oily medium of the'ink tospread outwards owing to the capillary attraction of the material ofwhich the impression receiving sur face consists, thus forming a borderof oil about the heavily inked portion which naturally detrimentallyaffects the appearance of the reproduction.

The invention consists broadly in break ing up what would be the solidlyinked portion of the reproduction so as to provide portions thereinwhich do not receive ink directly but only as the result of thespreading of the ink passing through the open portions in the stencilcoating, and leaving the ground intervening between what would be thesolidly inked portions free from ink.

Thus in accordance with the invention the stencil may be formed or beprovided with dots, lines or reticulations which will resist" thepassage of ink throu h the stencil at what would normally be t e openportions thereof, while the remaining portion of the stencil is entirelyimpervious to the ink.

These dots, lines or reticulations may, in

accordance with the invention, beformed by treating the layer ofcomposition to be employed in the production of the stencil, as byexposure to light, so as to form thereon dots, linesor reticulationsconstituted by portions of the compositionwhich have been renderedinsoluble.

Thus, for instance, the layer of composition on a suitable support whichmay be of the character of the carbon tissue employed in the carbonprocess, is exposed to light under a screen provided with opaque orlight resisting dots, lines or reticulations.

A dotted screen adapted for use, in accordance with the invention may beformed b exposing a photographic plate behind a half tone screen anddeveloping and fixing the photographic image thus produced.

The layer of composition on the support after treatment in the mannerindicated is ready for use in the production of stencils, by exposure tolight under suitable positlves or negatives. and by such furthertreatment as is described in the patents mentioned, after whichtreatment the stencils may be used in accordance with the descriptioncontained in such patents in the production of prints or impressions.

According to another phase of'the invention the sensitized plateemployed in producing the negative of the matter to be reproduced isexposed in order to produce on the plate in succession an image of thematter to be reproduced and an image of a screen formed with lines, dotsor reticulations.

The image of the matter to be-reproduced, or of the screen-may be formedfirst on the plate, after which the image of the screen, or of thematter to be reproduced may be formed thereon, the negative thusproduced being. then used in making a positive which in turn is used inmaking the stencil.

The invention will be described in detail, and by way of example, withreference to the accompanying drawings, in which Figures 1 and 2 areviews respectivel in plan and section of a support 1 provlded with alayer of light sensitive composition 2.

after exposure to light according to one mode of carrying the inventioninto effect, the lines 4 thereon rep-resenting the portions of the lightsensitive composition which have been rendered insoluble.

Figures 6 and 7 are similar views of the coated support after it hasbeen exposed to light behind a diapositive of the letter S to bereproduced, the hatched portion 5 representing the insolubilizedcomposition formed as the result of such exposure. On development thewhite portions intervening between the lines 4 will be washed away andin use, as Will be understood, this stencil will only allow ink to passthrough the parts of the sup-port from which the soluble matter has beenremoved with the result that the representation formed with the aid ofthe stenoil will be composed of dots arranged to form the letter S. 1

Figure 8, 9, 10 and 11 illustrate another mode of carrying the inventioninto effect, Figure 8 being a plan view of a sensitized plate, that isto say, a photographic plate of the usual kind which has been exposed inorder to produce on the plate an image of the letter S, the hatchedportions 6 thereon indicating the light affected portions of the plateand 7 the portions which have not been affected by light.

Figure 9 is a plan view of the plate after it has been again exposedunder a lined screen, such exposure causing the formation of dots 8 onthe portion of the plate which had not in the previous exposure beenacted upon by light. After development in the usual way this plate isarranged over a glass plate coated with an emulsion such as is used inmaking lantern slides, the whole being then exposed to the action oflight in a printing frame or the like with the result that adiapositive, as illustrated in Figure 10 in which 9 represents thesurrounding portions of the plate which have not been affected by light,10 the portion thereof in the form of dots which have also not beenaffected by light, and 11 the lines intervening between such portions,is obtained. The diapositive thus produced is then employed in makingthe stencil by arranging the same over a support provided with a coatingof bichromated gelatine such as is illustrated in Figures 1 and 2. Onexposure a print will be obtained, as indicated in Figure 11, in which12 represents the portion of the field surrounding the image which willconstitute ink impermeable areas, the representation of the matter to bereproduced forming ink permeable foraminous areas of which 13 representsink resisting elements in the form of. dots and 14: ink permeable spacesin the form of lines between said dots.

The present invention, it may be pointed out, extends not only to theproduction of stencils in the manner indicated and to the use of suchstencils but also consists in a support provided with a layer of lightsensitive composition which has been provided with lines, dots orreticulations which will resist the passage of ink throu h the stencilat what would normally be t e open portions thereof, such lines, dots orreticulations being formed, for example, on the light sensitive surfaceby photographic action.

, While in the above description reference has been made to bichromatedelatine as the light sensitive composition, it is to be understood thatother light sensitive compositions of the character indicated, as forinstance bitumen, may be employed.

In conclusion it may be pointed out that it is of the essence of theinvention that the stencilled reproduction shall have pure whites, thatis to say shall have, for instance, a ground which receives no ink andis therefore distinguished from the ground which would be produced bymeans of a half tone negative or positive and an image or impressionconstituted by an inked surface which is broken up or an inked groundwhich is broken up and an image or impression thereon in pure white thatis to st y an image or impression constituted by a surface whichreceives no ink.

Having now particularly described and ascertained the nature of my saidinvention, and in What manner the same is to be performed, I declarethat what I claim is l. The process of forming stencils for use induplicating, which comprises producing by the agency of light aphotographic image of the matter to be reproduced and an image of ascreen in superposition on a layer of composition which is renderedinsoluble in a developer by the action of light and treating the layerof composition with a developer to remove the still soluble portionsthereof.

2. The process of forming stencils for use in duplicating whichcomprises exposing a layer of bichromated gelatine to the action oflight to form in succession an image of the matter to be reproduced andan image of a screen in superposition and developing the exposed layerwith warm water to remove the portions thereof which have not beenaffected by light.

3. The process of forming stencils for use in duplicating whichcomprises exposing a layer of bichromated gelatine coated on a temporarysupport to the action of light to form an image of the matter to bereproduced and an image of a screen in superposition, developing theexposed layer with warm water to remove the portions thereof which havenot been aifected by light and transferring the developed image on to asheet of porous flexible material;

4. Theprocess of forming stencils for use 1n dupl cating WhlOhcomprises. exposing a layer of bichromated gelatine coated on atemporary support to the action of light to form an image of the matterto be reproduced and an image of a screen in superposition, developingthe exposed layer with warm water to remove the portions thereof whichhave not been aifected by light and transferring the developed image onto a sheet of Yoshino paper.

5. A stencil comprising a porous flexible support, an ink resistingmaterial distributed thereover and forming thereon ink impermeable areasand "foraminous areas adapted to permit the passage of ink in using thestencil.

6. A stencil comprising a porops flexible support, a coating ':of acomposition rendered insoluble by the action of light adhering by inkareas constituted bya plurality of smaller areas of said compositionspaced apart and adapted to permit in using the stencil the passage ofink through the spaces. inter- Venin between the smaller areas.

7. stencil comprising a porous flexible thereto, said layer beingconstituted support, a light affected bichromated gela tine compositiondistributed thereover to form foraminous and non-permeable areasequivalent respectively to the normally solidly inked portion ofv thereproduction and the spaces intervening between such por-- tlons.

In testimony whereof I have signed my 7 name to this specification;

DAVID GESTETNER.

impermeable areas and foraminous

